Many cue sticks have two or sometimes three stick portions which are joined together by joints that allow the assembly or disassembly of the stick portions. Generally, each joint consists of one joint member secured to one stick portion and a mating joint member secured to the adjacent stick portion which, when engaged, couple the stick portions together.
Some cue stick joints include a coupling rod of one joint member secured to one stick portion and a sleeve of the other joint member secured to the other stick portion. The coupling rod has a male threaded region and a centering pin. The sleeve has a bore for receiving the centering pin of the coupling rod to axially align the coupling rod with the sleeve and a female threaded region for engaging with the male threaded region to secure the coupling rod and sleeve together, thereby securing the two stick portions together. A tight fit between the centering pin of the coupling rod and the bore of the sleeve is generally desirable for keeping the coupling rod and sleeve in axial alignment, which in turn keeps the mating stick portions axially aligned. Cue stick portions that are axially aligned are desired for obtaining optimum performance of the cue stick.
When there is a tight fit between the centering pin of the coupling rod and the bore of the sleeve, the coupling rod and the sleeve must be installed within their respective stick portions with precision in order to axially align the coupling rod and sleeve along the axis of the stick portions. If the coupling rod and the sleeve are axially misaligned with their respective stick portions, the coupling rod and sleeve will secure to each other in axial alignment but the stick portions will be axially misaligned with each other. Axial misalignment of the stick portions of a cue stick is not only unsightly but also results in reduced performance of the cue stick.
The present invention includes a joint for a sports stick that allows for some misalignment between the joint members and the respective stick portions while still enabling the stick portions to be joined together in axial alignment.
The present invention provides a joint for a sports stick having first and second stick portions which includes a first joint member for securing to the first stick portion. The first joint member includes a coupling rod having a joint securing male threaded region and a centering pin. A second joint member is included for securing to the second stick portion. The second joint member has a cavity for receiving the coupling rod. The receiving cavity includes a joint securing female threaded region, a loose fit inner diameter, and a close fit inner diameter region positioned between the female threaded region and the loose fit inner diameter region. The male threaded region of the coupling rod engages with the female threaded region of the receiving cavity for securing the first and second joint members together and the centering pin closely engages the close fit inner diameter region. The female threaded region and the loose fit inner diameter region are dimensioned with enough clearance relative to the male threaded region and the centering pin of the coupling rod to allow compensation for misalignment.
In preferred embodiments, the close fit inner diameter region can have a tapered entrance. The close fit inner diameter region is sufficiently short in axial length, and the clearance of the female threaded region and the loose fit inner diameter region relative to the male threaded region and the centering pin of the coupling rod is sufficiently large to allow pivoting of the coupling rod about the close fit inner diameter region. A grippable insert is positioned within the receiving cavity of the second joint member adjacent to the close fit inner diameter region for gripping the centering pin of the first joint member. The grippable insert is compressible and is often an xe2x80x9cOxe2x80x9d ring. The first joint member includes a collar encircling the joint securing male threaded of the coupling rod for protecting the male threaded region. The first and second joint members include secondary male threaded regions for securing the first and second joint members to the first and second stick portions, and a smooth outer diameter region with a glue groove adjacent to the secondary male threaded regions for securement within alignment holes. In some embodiments, the first and second joint members can engage together in less than three revolutions, and some can engage in about one revolution. Commonly, the first and second joint members secure the first and second stick portions of a cue stick together.
The present invention also provides a joint for a sports stick having first and second stick portions including a first joint member for securing to the first stick portion. The first joint member includes a coupling rod having a joint securing male threaded region and a centering pin. A second joint member is included for securing to the second stick portion. The second joint member has a cavity for receiving the coupling rod. The receiving cavity includes a joint securing female threaded region and a close fit structure. The male threaded region of the coupling rod engages with the female threaded region of the receiving cavity for securing the first and second joint members together and the centering pin closely engages the close fit structure. The female threaded region is dimensioned with enough clearance relative to the male threaded region and the close fit structure is sufficiently short in length to allow compensation for misalignment.
The present invention additionally provides a joint for a sports stick having first and second stick portions including a first joint member for securing to the first stick portion. The first joint member includes a coupling rod having a joint securing male threaded region and a centering pin. A second joint member is included for securing to the second stick portion. The second joint member has a cavity for receiving the coupling rod. The receiving cavity includes a joint securing female threaded region and a bore region. The male threaded region of the coupling rod engages with the female threaded region of the receiving cavity for securing the first and second joint members together and the centering pin engages the bore region. The centering pin and the bore region closely engage each other along a short axial close engagement length. The female threaded region is dimensioned with enough clearance relative to the male threaded region and the close engagement length is sufficiently short in length to allow compensation for misalignment.
The present invention further includes a method of coupling first and second stick portions of a sports stick together including securing a first joint member to the first stick portion. The first joint member includes a coupling rod having a joint securing male threaded region and a centering pin. A second joint member is secured to the second stick portion. The second joint member has a cavity for receiving the coupling rod. The receiving cavity includes a joint securing female threaded region, a loose fit inner diameter region, and a close fit inner diameter region positioned between the female threaded region and the loose fit inner diameter region. The male threaded region of the coupling rod is engaged with the female threaded region of the receiving cavity for securing the first and second joint members together and the centering pin is closely engaged with the close fit inner diameter region and loosely engaged with the loose fit inner diameter region. The female threaded region and the loose fit inner diameter region are dimensioned with enough clearance relative to the male threaded region and the centering pin of the coupling rod to allow compensation for misalignment.
In the present invention, by allowing pivoting of the coupling rod of the first joint member about the close fit inner diameter region within the receiving cavity of the second joint member, the joint can compensate for axial misalignment of the joint members with their respective stick portions so that the stick portions can still be joined together in axial alignment. This makes it easier for stick portions of sports sticks to be interchangeable. In addition, the joint members can be installed within the stick portions with less precision.